Figure 4. Identification of PEGylation site and spatial structure of GPx1M. (A) The peptide sequences derived from GPx1M digestions with trypsin. (B) The peptide sequences derived from SS-mPEG-GPx1M digestions with trypsin. (C) The ESI-MS analysis of peptides from digested GPx1M. (D) The structure of GPx1M with side chains shown as sticks.